The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 56th year, we are closing in on 350,000 sequences, and we’ve crossed 9,700 citations (which often say “discovered thanks to the OEIS”).

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A003190 Number of connected 2-plexes. (Formerly M3121) 1
 1, 0, 1, 3, 29, 2101, 7011181, 1788775603301, 53304526022885278403, 366299663378889804782330207902, 1171638318502622784366970315262493034215728, 3517726593606524901243694560022510194169866584119717555335 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 COMMENTS The Palmer reference (incorrectly) has a(7)=7011349, a(8)=1788775603133, a(9)=53304526022885278659. - Sean A. Irvine, Mar 05 2015 Also connected 3-uniform hypergraphs on n vertices. - Gus Wiseman, Feb 23 2019 REFERENCES N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS P. J. Cameron, Sequences realized by oligomorphic permutation groups, J. Integ. Seqs. Vol. 3 (2000), #00.1.5. E. M. Palmer, On the number of n-plexes, Discrete Math., 6 (1973), 377-390. FORMULA Inverse Euler transform of A000665. - Sean A. Irvine, Mar 05 2015 EXAMPLE From Gus Wiseman, Feb 23 2019: (Start) Non-isomorphic representatives of the a(5) = 29 2-plexes:   {{125}{345}}   {{123}{245}{345}}   {{135}{245}{345}}   {{145}{245}{345}}   {{123}{145}{245}{345}}   {{124}{135}{245}{345}}   {{125}{135}{245}{345}}   {{134}{235}{245}{345}}   {{145}{235}{245}{345}}   {{123}{124}{135}{245}{345}}   {{123}{145}{235}{245}{345}}   {{124}{134}{235}{245}{345}}   {{134}{145}{235}{245}{345}}   {{135}{145}{235}{245}{345}}   {{145}{234}{235}{245}{345}}   {{123}{124}{134}{235}{245}{345}}   {{123}{134}{145}{235}{245}{345}}   {{123}{145}{234}{235}{245}{345}}   {{124}{135}{145}{235}{245}{345}}   {{125}{135}{145}{235}{245}{345}}   {{135}{145}{234}{235}{245}{345}}   {{123}{124}{135}{145}{235}{245}{345}}   {{124}{135}{145}{234}{235}{245}{345}}   {{125}{135}{145}{234}{235}{245}{345}}   {{134}{135}{145}{234}{235}{245}{345}}   {{123}{124}{135}{145}{234}{235}{245}{345}}   {{125}{134}{135}{145}{234}{235}{245}{345}}   {{124}{125}{134}{135}{145}{234}{235}{245}{345}}   {{123}{124}{125}{134}{135}{145}{234}{235}{245}{345}} (End) CROSSREFS Column k=3 of A301924. Cf. A000665 (unlabeled 3-uniform), A025035, A125791 (labeled 3-uniform), A289837, A301922, A302374 (labeled 3-uniform spanning), A302394, A306017, A319540, A320395, A322451 (unlabeled 3-uniform spanning), A323292-A323299. Sequence in context: A182385 A255597 A319637 * A322451 A213792 A133663 Adjacent sequences:  A003187 A003188 A003189 * A003191 A003192 A003193 KEYWORD nonn,nice AUTHOR EXTENSIONS a(7)-a(9) corrected and extended by Sean A. Irvine, Mar 05 2015 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 9 03:23 EST 2021. Contains 349625 sequences. (Running on oeis4.)